2007 OPEL Astra car cutting off power while driving, when pressing horn it does not but it up the radio volume problems

1. When pressing the Horn, instead of hooting
the car is turning up the volume of the radio

2. While the Opel is in motion the dashboard
lights, window buttons and radio goes off
causing loss of power for 5 to 15 seconds
reducing engine power / limp mode then the
lights on the dashboard comes back then
everything is back to normal. Then after
driving for about a kilometer this happens
again.

Problems:

1. When pressing the Horn, instead of hooting
the car is turning up the volume of the radio

2. While the Opel is in motion the dashboard
lights, window buttons and radio goes off
causing loss of power for 5 to 15 seconds
reducing engine power / limp mode then the
lights on the dashboard comes back then
everything is back to normal. Then after
driving for about a kilometer this happens
again.